1. Technical Field
The present invention relates to a semiconductor device, a method of manufacturing a semiconductor device, a mold, and a sealing device.
2. Related Art
In recent years, a semiconductor device having a configuration where a semiconductor chip is sealed with a sealing resin in a state where a plane (rear surface) opposite to a plane (front surface) of a die pad (island portion), on which a semiconductor pallet or a semiconductor chip is mounted, of a lead frame is exposed (hereinafter, referred to as “exposed die pad-type packages”) has been developed. In such an exposed die pad-type package, the exposed surface of the die pad is connected to an electrode on a circuit board through a solder. In this manner, the die pad may serve as an external electrode with a low resistance. In addition, the die pad may serve as a heat dissipation path that transfers heat generated in the semiconductor chip to the outside. Therefore, the semiconductor device has been used especially as a high power consumption device.
However, in regard to the exposed die pad-type package of the related art, there is a problem in that in an encapsulation process with the sealing resin by using an encapsulation mold, the sealing resin flows into the rear surface of the die pad and therefore a resin burr is formed on the rear surface that is the exposed surface of the die pad. When such a resin burr is formed, there is a problem in that a part of the heat dissipation path is blocked out by the resin burr, or the like.
Japanese Laid-Open Patent Publication No. 2001-035868 discloses a configuration where a tapered portion is provided at the periphery of the heat dissipation plate (die pad) surface of the lead frame, and an encapsulating mold that is a lower mold is provided with a concave portion at a position that comes into contact with a heat dissipation plate. In this manner, the periphery of the heat dissipation plate and the encapsulation mold are engaged, and thereby it is regarded that the leakage of the resin toward a surface of the heat dissipation plate is prevented during the encapsulation with the resin. Therefore, a process of removing the resin burr after the sealing with the resin may be omitted.
FIG. 37 represents a cross-sectional view illustrating a configuration of a semiconductor device disclosed in Japanese Laid-Open Patent Publication No. 08-046090. In this Japanese Laid-Open Patent Publication No. 08-046090, a technique for solving the following problems is disclosed. After a semiconductor chip (silicon) is sealed with a sealing resin (plastic), the sealed semiconductor chip is taken out from a mold. Then, at the boundary 38 of silicon, plastic, and air, the plastic contracts during cooling from a temperature of a transfer mold. At this time, since the plastic contracts more than the silicon, due to a difference in a thermal contraction, a tension is generated at the boundary of the silicon, plastic, and air. Therefore, there is a problem in that separation occurs frequently at the boundary of the silicon, plastic, and air. Japanese Laid-Open Patent Publication No. 08-046090 discloses a configuration where a plastic molded main body 32 is provided with a notch 37 to maintain an adhesion portion in a close contact state where the adhesion portion is sealed from the atmosphere, to diminish the tension at the boundary of the silicon, plastic, and air, and to mostly prevent the adhesion region from being affected by the plastic main body 32. There is disclosed that such a notch can be easily formed, for example, by a distinct feature portion formed in the lower mold. In addition, there is described that one of various shapes and configurations may be selected (Paragraph 0030, FIG. 8, or the like).